Current-induced spin polarisation in Rashba-Dresselhaus systems under different point groups
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arXiv
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| Format: | Preprint |
| Publié: |
2024
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| _version_ | 1866909513256271872 |
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| author | Dey, Akash Nandy, Ashis K. Saha, Kush |
| author_facet | Dey, Akash Nandy, Ashis K. Saha, Kush |
| contents | Non-magnetic materials without inversion symmetry typically exhibit strong Rashba spin-orbit coupling (SOC), enabling the well-known Rashba Edelstein effect where an external electrical current induces transverse spin polarisation. In this study, we demonstrate that electrically induced spin polarisation in non-magnetic materials, for example, electronic systems within quantum-well geometries, can significantly be influenced by the system's point-group symmetries, such as $C_n$ and $C_{nv}$. These symmetries allow various linear and higher-order momentum, $k-$varying SOC Hamiltonian. Specifically, we show that surfaces having $C_{n}$ point-group symmetry, which permits specific linear and cubic Rashba and Dresselhaus SOC terms, can lead to both orthogonal and non-orthogonal spin polarisations with respect to the applied field. In contrast, surfaces with $C_{nv}$ symmetry exhibit only transverse spin polarisation, regardless of the linear and cubic SOC terms. We further find contrasting spin polarisation for cubic-in-$k$ SOC as compared to the linear-in-$k$ SOC when energy is varied, for example, through doping. Additionally, we show that the surfaces with $C_{n}$ symmetry may exhibit persistent spin current, depending on the relative strength between different momentum-dependent SOC terms. Our finding emphasizes the significance of crystal symmetry in understanding and manipulating induced spin polarisation in noncentrosymmetric materials, especially in surface/interface systems. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2408_05188 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Current-induced spin polarisation in Rashba-Dresselhaus systems under different point groups Dey, Akash Nandy, Ashis K. Saha, Kush Mesoscale and Nanoscale Physics Non-magnetic materials without inversion symmetry typically exhibit strong Rashba spin-orbit coupling (SOC), enabling the well-known Rashba Edelstein effect where an external electrical current induces transverse spin polarisation. In this study, we demonstrate that electrically induced spin polarisation in non-magnetic materials, for example, electronic systems within quantum-well geometries, can significantly be influenced by the system's point-group symmetries, such as $C_n$ and $C_{nv}$. These symmetries allow various linear and higher-order momentum, $k-$varying SOC Hamiltonian. Specifically, we show that surfaces having $C_{n}$ point-group symmetry, which permits specific linear and cubic Rashba and Dresselhaus SOC terms, can lead to both orthogonal and non-orthogonal spin polarisations with respect to the applied field. In contrast, surfaces with $C_{nv}$ symmetry exhibit only transverse spin polarisation, regardless of the linear and cubic SOC terms. We further find contrasting spin polarisation for cubic-in-$k$ SOC as compared to the linear-in-$k$ SOC when energy is varied, for example, through doping. Additionally, we show that the surfaces with $C_{n}$ symmetry may exhibit persistent spin current, depending on the relative strength between different momentum-dependent SOC terms. Our finding emphasizes the significance of crystal symmetry in understanding and manipulating induced spin polarisation in noncentrosymmetric materials, especially in surface/interface systems. |
| title | Current-induced spin polarisation in Rashba-Dresselhaus systems under different point groups |
| topic | Mesoscale and Nanoscale Physics |
| url | https://arxiv.org/abs/2408.05188 |